Filtrado de una solución – Filtering for a solution

It has been my pleasure to work on this article with Soledad Obregon, a graduate student at the Technological Institute of Buenos Aires (Instituto Tecnológico de Buenos Aires, or ITBA). This article will be in Spanish and English, and to honor the success that the ITBA group had in Corrientes, Argentina, this article will be in Spanish and then an English translation will follow.

Water is one of the most basic human needs, yet is one of the most difficult problems facing society. Most of us, however, really do not put much thought into the water we use. We may get upset if a local river or lake becomes polluted, but most of us will dump products down the drain without really thinking about where that stuff goes. Then there are the issues of using chemicals in our homes and yards. Some of those toxins ends up in the local bay or river; but there's a good chance it seeps into our groundwater.

Many developing, and developed countries, rely on groundwater to meet their population's needs. Groundwater subsidence, or sinking, is one unfortunate result. In the United States, from the San Joaquin Valley to the New Orleans area, environmental and structural problems resulting from extracting groundwater is presenting civil engineers all kinds of dilemmas. Contamination, however, is another long term problem that can leave horrific effects on people for generations.

One such affected region is Corrientes, a province in northeast Argentina that is home to about 930,000 people. Corrientes has a special place in Argentines' hearts, as Paraguay's attack on this province sparked Argentina to declare war on its neighbor during the nineteenth century War of the Triple Alliance, the bloodiest and most destructive war ever in South America. But now Corrientes is facing many problems: its economy is stagnant, with per capita income half of the national average; a legacy of land ownership concentrated among a few wealthy families has subjected too many of its residents to poverty; and much of Argentina's political volatility has its epicenter in Corrientes. Lying between two large rivers, Corrientes also deals with the frequent threat of floods. Finally, many of its residents rely on groundwater for their daily household and farming needs, and therein lies a disturbing threat: water throughout this province contains high levels of arsenic.

Unfortunately, local governments, strapped for cash, really cannot do much to implement scalable solutions to combat the threat of arsenic. Arsenic formation often occurs naturally, by volcanic activity or natural chemical and biological reactions. Treating arsenic levels is expensive and consumes much energy. But there is a solution on the way. Led by Professor María Marta Fidalgo, a group of researchers and graduate students at the Technological Institute of Buenos Aires (ITBA) has developed a technology to filter out arsenic and other contaminants, using little energy and at a low cost.

Fidalgo's team, using nanotechnology, embeds tiny iron oxide particles on tiny porous aluminum tubes, developing tube-like ceramic pipes that works as filters. As water is forced through the tube walls, arsenic is retained in these filters. The process is called adsorption, defined as the adhesion of molecules to a surface. Let me explain in laypersons' terms: you are a chocolate chip fiend, and you want to maximize the amount you use when you bake a cake. You can bake a huge cake and layer the chips on the top and sides. Or, you can cut the cake in many different pieces (or make cupcakes!), and cover all the surfaces, using more chocolate chips in the process.

The beauty of this technology is that the membranes do not have to be replaced; the filters just need to be periodically depending on the amount of water filtered and levels of concentrated arsenic that is accumulated. The resulting waste gathered in those filters then can be safely disposed. The membranes are relatively cheap, too: one of her students, Soledad Obregon, explained to me that they only cost around 9 euros each.

This technology has already found success: without any funding from government or the private sector, Fidalgo's team researched and developed the technology. The only funding they received were from ITBA, and Perez Companc S.A., an Argentinian energy company, donated the laboratory space in which the team worked. Last year, the ITBA's team traveled to Stutgart, Germany, to participate in Mondialogo, a technical conference sponsored by UNESCO and Daimler. Parterning with Pennsylvania's Lehigh University, they won the silver award in the engineering competition. With the 10,000 euros awarded to them, they are now distributing the filters in Sauce, a rural town of about 9,000 people in southwest Corrientes. The team is traveling to Corrientes for 10 days in February, so I expect a follow-up report from them!

It is Fidalgo and her team's hope that their technology can spread not only throughout Corrientes, but throughout Argentina and beyond its borders through Latin America. The main issue is funding: right now their team is donating their filters to Sauce residents, but they could use some financial help. To learn more, please contact Obregon here.

We hear a lot about activists in the world of sustainability, but truthfully, it is engineers and scientists like Fidalgo and her studens that will find the most cost effective solutions. We need more of them.